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* [U-Boot-Users] 2-step U-boot(?)
@ 2008-06-09  4:31 Frank Wei
  2008-06-09  4:56 ` Stefan Roese
  2008-06-09  5:50 ` Wolfgang Denk
  0 siblings, 2 replies; 3+ messages in thread
From: Frank Wei @ 2008-06-09  4:31 UTC (permalink / raw)
  To: u-boot

Hello,

I'm new to u-boot. Has anybody tried to make 2-step u-boot? I mean a really small u-boot (the first u-boot) possible only needs to initialize the CPU, memory... and load the full featured (the second u-boot) u-boot and the Linux to the RAM. In this way the second u-boot as an application can be updated on the fly.

Could you please share your knowledge here If you have done the job or the similar?

Regards,
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* [U-Boot-Users] 2-step U-boot(?)
  2008-06-09  4:31 [U-Boot-Users] 2-step U-boot(?) Frank Wei
@ 2008-06-09  4:56 ` Stefan Roese
  2008-06-09  5:50 ` Wolfgang Denk
  1 sibling, 0 replies; 3+ messages in thread
From: Stefan Roese @ 2008-06-09  4:56 UTC (permalink / raw)
  To: u-boot

On Monday 09 June 2008, Frank Wei wrote:
> I'm new to u-boot. Has anybody tried to make 2-step u-boot? I mean a really
> small u-boot (the first u-boot) possible only needs to initialize the CPU,
> memory... and load the full featured (the second u-boot) u-boot and the
> Linux to the RAM. In this way the second u-boot as an application can be
> updated on the fly.
>
> Could you please share your knowledge here If you have done the job or the
> similar?

Yes, there already is a framework for a 2-stage U-Boot booting in place. Take 
a look at the nand_spl (NAND Secondary Program Loader) infrastructure:

nand_spl/*
doc/README.nand-boot-ppc440

Here a small (4k) image is build which only inits the basic CPU stuff, RAM and 
NAND controller. Then a full-blown U-Boot image is loaded from NAND.

Best regards,
Stefan

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

^ permalink raw reply	[flat|nested] 3+ messages in thread

* [U-Boot-Users] 2-step U-boot(?)
  2008-06-09  4:31 [U-Boot-Users] 2-step U-boot(?) Frank Wei
  2008-06-09  4:56 ` Stefan Roese
@ 2008-06-09  5:50 ` Wolfgang Denk
  1 sibling, 0 replies; 3+ messages in thread
From: Wolfgang Denk @ 2008-06-09  5:50 UTC (permalink / raw)
  To: u-boot

In message <52CF207E00A9394C8CD1423668654840A8B3DB1E@4rf-nz-exch02.local.4rf.com> you wrote:
>
> I'm new to u-boot. Has anybody tried to make 2-step u-boot? I mean a really
>  small u-boot (the first u-boot) possible only needs to initialize the CPU,
>  memory... and load the full featured (the second u-boot) u-boot and the Li

As Stefan already pointed out, booting from NAND involves exactly such
a scenario.

> nux to the RAM. In this way the second u-boot as an application can be upda
> ted on the fly.

However I don;t really understand what this has to do with the
capability to update U-Boot? You can update U-Boot as is just fine.

> --_000_52CF207E00A9394C8CD1423668654840A8B3DB1E4rfnzexch02loca_
> Content-Type: text/html; charset="us-ascii"
> Content-Transfer-Encoding: quoted-printable
> 
> <html>

Please never post HTML to this list!

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Never worry about theory as long as  the  machinery  does  what  it's
supposed to do.                                      - R. A. Heinlein

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2008-06-09  5:50 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2008-06-09  4:31 [U-Boot-Users] 2-step U-boot(?) Frank Wei
2008-06-09  4:56 ` Stefan Roese
2008-06-09  5:50 ` Wolfgang Denk

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